Refrigerating system with osmotic membrane

ABSTRACT

In the preferred form of this refrigerating system, the refrigerant condensing in the condenser is fed to the upper compartment of a receiver boiler in which a membrane having osmotic properties passes the liquid refrigerant into the lower compartment where it is vaporized by a heater. This vapor passes through the primary venturi passage of an aspirator which discharges into the top of the condenser. Some refrigerant liquefied in the condenser flows successively through one heat exchanger passage and a restrictor and an evaporator and the second passage of the heat exchanger to the low-pressure suction inlet of the aspirator.

Q mted States Patent 1 51 3,645,111

Williamms 1 Feb. 29, 1972 [54] R-EFRIGERATING SYSTEM WITH 3,519,066 7/1970 Anderson ..62/498 OSMOTIC MEMBRANE Primary Examiner-Meyer Perlin [72] Inventor: Victor A. wllllamltis, Dayton, Ohio Assistant Examiner Rona|d capossena [73] Assigneez General Motors Corporation Detroit, Attorney-William S. Pettigrew and Frederick M. Ritchie 57 ABSTRACT [22] Filed 1970 In the preferred form of this refrigerating system, the [21] Appl. N0.: 85,380 refrigerant condensing in the condenser is fed to the upper compartment of a receiver boiler in which a membrane having osmotic properties passes the liquid refrigerant into the lower [52] US. Cl. ..62/498, 62/115, 417/48 compartment where it is vaporized by a beaten [51] Int. Cl ..F25b 29/00 [58] Field at Search ..417/48; 62/1 15, 116,498,500 Thls vapor Passes through the p y venwfl P g of an aspirator which discharges into the top of the condenser. [56] References Cited Some refrigerant liquefied in the condenser flows successively through one heat exchanger passage and a restrictor and an UNITED STATES PATENTS evaporator and the second passage of the heat exchanger to the low-pressure suction inlet of the aspirator. 2,904,969 9/1959 Reamer ..62/ 174 3,427,978 2/1969 Hanneman et al ..417/48 4 Claims, 6 Drawing Figures PATENTEDFEB 29 I972 zwzi/ /i ifa AT ORNEY REFRIGERATING SYSTEM WITH OSMOTIC MERANE Compressors of the most widely used refrigerating systems are complicated, costly and subject to wear. Some types of absorption systems have been used but these systems had difficulty in attaining low temperatures and satisfactory efficiency and are expensive to build.

It is an object of this invention to provide a new refrigerating system without moving parts which can attain low temperatures and satisfactory efficiency.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIG. 1 is a diagrammatic illustration partly in section of a refrigerating system embodying one form of my invention;

FIG. 2 is a sectional view illustrating a second form of receiver-boiler shown in FIG. 1;

FIG. 3 is a perspective view partly in section of a third form of receiver-boiler shown in FIG. 1;

FIG. 4 is an enlarged sectional view of one of the elements of the receiver-boiler shown in FIG. 3;

FIG. 5 is a sectional view similar to FIG. 4 and showing a second modified form of one of the elements shown in FIG. 3; and

FIG. 6 is a sectional view of a fourth form of receiver-boiler which may be used in the system shown in FIG. 1.

Referring now more particularly to FIG. 1, there is shown diagrammatically a condenser having inlet means 21 and outlet means 22 with one branch 24 draining into the upper compartment 26 of a receiver-boiler or receiver-vaporizer (compressor) 28 which is in the form of a cylindrical metalwalled enclosure. A horizontally extending membrane 30 separates the upper compartment 26 from the lower compartment 32. This membrane preferably is an elastomer having osmotic properties. The lower compartment 32 is heated by an electric heater 34 or some other suitable form of heating means. The bottom of the receiver-boiler 28 is insulated by some form of heat-insulating means 36. The upper and lower halves of the receiver-boiler are separated by a leakproof, thermal insulating gasket 35 held by low-conduction stainless steel bolts 37.

An outlet conduit 38 provided with heat insulation 40 extends to the inlet 39 of a venturi-type aspirator 42. This inlet connects to the venturi passage extending through the aspirator 42 to an outlet 41 connecting with a discharge conduit which connects with the top of the condenser 20.

The second branch 44 of the outlet means 22 of the condenser 20 connects with an evaporative circuit 45. The circuit includes a conduit 46 which, in turn, connects with the helical passage of a heat exchanger 48. The outlet of this helical passage connects to one end of a restrictor 50 serving as a flow control device for controlling the flow of refrigerant into the bottom of an evaporator 52. The top of the evaporator 52 connects with the interior passage of the heat exchanger 48 from which point the evaporator refrigerant is delivered to the secondary low-pressure entrance 53 of the aspirator 42 which connects with the interior of the venturi of the aspirator 42. I It is known that refrigerants will leak through elastomeric hoses in automobile air-conditioning systems. Elastomers and many other materials have osmotic properties by which liquids will flow through them b osmosis even against an opposing differential in pressure. The refrigerating system of this invention takes advantage of such properties. Performance depends upon the maintenance of a temperature differential across the relatively thick membrane 30 so that one-way refrigerant flow can occur against a higher pressure in the compartment 32. Such flow occurs because liquid refrigerant is kept continuously in contact with the low-pressure side of the membrane exposed to the compartment 26. This seemingly uphill flow is made possible by the refrigerant concentration gradient on a liquid/vapor mass at any given temperature.

In the preferred form a silicone elastomer is used as the membrane 30. The refrigerant known as R-l2 is preferred. In operation the refrigerant condenses in the condenser 20 and drains into the upper compartment 26 of the receiver-boiler 28. The electric heater 34 heats any refrigerant in the compartment 32 in vapor form. The high concentration of refrigerant molecules (liquid refrigerant) along the upper surface of the membrane 30, as contrasted to the low concentration of refrigerant molecules (refrigerant vapor) along the bottom surface of the membrane 30 causes a movement of the molecules of the refrigerant through the membrane 30 from the upper chamber 26 into the lower chamber 32 where the heater turns it into vapor and creates a vapor pressure in the compartment 32.

The relatively low temperature of the condenser 20 and upper chamber 26 and the relatively high temperature in the compartment 32 provided by the heater 34 creates a pressure differential which causes a sequential flow of refrigerant vapor from the compartment 32 through the conduit 38, the aspirator 42, and the conduit 44 to the condenser 20. The venturi action in the aspirator 42 causes a much lower pressure at its secondary entrance 53. This causes a flow of refrigerant from the outlet means 22 of the condenser through the second branch 44 thereof and the conduit 46 to heat exchanger 48 and the restrictor 50 into the evaporator 52. The lower pressure caused by the suction at the secondary entrance 53 and therestrictor 50 causes evaporation within the evaporator 52 to cool the compartment illustrated by the diagrammatic enclosure 54. The evaporated refrigerant flowing out of the evaporator 52 to the secondary entrance 53 cools the warmer liquid refrigerant flowing from conduit 46 to the restrictor 50, thereby to effect a heat transfer which improves the systems thermal efficiency.

If desired, other refrigerants may be used such as that known as R-2l (Dichloromonofluoro methane) or R-22 (Monochlorodifluoro methane). Also, under certain conditions the refrigerant known as R-ll (Trichloromonofluoro methane) and R-l l3 (Trichlorotrifluoro ethane) and R-l l4 (Dichlorotetrafiuoro ethane) may be used. Also, other elastomers, other plastics, and other materials may be used for the membrane such as fluorosilicones, polychloroprenes, acrylonitrilebutadienes, styrenebutadienes, polyisobutylenes, ethylene-propylene polymers, natural or synthetic polyisoprenes, fluorinated elastomers, polysulfides, polyacrylates, chlorosulfonated polyethylenes, polyurethanes, and polybutadienes. The effectiveness of the elastomeric membrane selected will depend on the refrigerant used.

In FIG. 2, there is shown a modified form of receiver-boiler including a cylindrical enclosure of suitable low thermal conductivity metal, such as stainless steel, with cooling fins 29 and having an entrance pipe 124 leading to an upper compartment 126 with a membrane 130 separating the upper compartment from a lower compartment 132 containing an electric heater 134. The bottom is provided with suitable heat insulation such as glass fiber insulation 136 and the halves of the enclosure are separated by a leakproof, thermal break gasket 135.

In FIG. 3 there is shown another modified form of receiverboiler in which smaller cylindrical tubes 228 are connected in parallel and structurally connected by passing through aligned apertures in cooling fins 229. As shown in FIG. 4, a membrane 230 is generally cylindrical in shape with a corrugated outer surface. Liquid from the bottom of the condenser 20 flows through spaces 226 defined respectively between the outer surface of each membrane 230 and cylindrical tube 228 and then flows through the membrane 30 and a perforated cylinder 231 into the central axial compartment 232 which corresponds to the lower chamber 32 of FIG. 1. A coaxial electric heater coil 234 in the center of the chamber 232 beats any vapor or liquid therein as in FIG. t.

In the form shown in FIG. 5, a porous, sintercd metal or woven wire sleeve 326 is provided between the outer cylinder 328 and the membrane 330 for the reception of the liquid from the condenser. A perforated metal sleeve 3311 is provided between the membrane 330 and the coaxial inner compartment 332 which corresponds to the compartment 132 in FIG. 1 and contains a coaxial electric heater coil 334 corresponding to the heater 34 in FIG. 1. This form likewise includes transverse cooling fins 329 similar to F168. 3 and 4.

In FIG. 6, the receiver-boiler 428 is formed of an inverted cup-shaped metal member with cooling fins 429 and having an offset outer rim 425. There is also a similarly shaped upright member 423 upon the bottom having an offset rim 421, but formed of low heat-conductive high-strength plastic or reinforced plastic. The thick membrane 430 is clamped between the flanges 425 and 421 by suitable low conductivity, stainless steel bolts or rivets 437. A gasketed 435, leakproof gap is provided between the flanges to minimize conduction. The space within the inverted cup member 427 forms the upper compartment 426 for liquid entering through the entrance 424 from the condenser. The lower compartment 432 contains an electric heater 434 and is provided with heat insulation 436 and an outlet conduit 438. These correspond to the connections shown in FIG. 1 and operate in a similar manner.

While the embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is:

1. A refrigerating system including a receiver-vaporizertype compressor having an enclosure and a membrane dividing said enclosure into cooler first and warmer second compartments, a condenser having inlet and outlet means, said outlet means connected to said first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane having osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment.

2. A refrigerating system including a receiver-vaporizertype compressor having an enclosure and a membrane dividing said enclosure into cool first and hot second compartments, a condenser having inlet and outlet means, said outlet means connected to said first first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane having osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment, said, evaporate circuit including a heat exchanger having a first portion between the inlet of said evaporative circuit and said restrictor and having a second portion between said evaporator and the outlet of said evaporative circuit, said first and second portions being in heat exchange relation.

3. A refrigerating system including a receiver-vaporizer comprising a cool cylindrical imperforate outer tube and a cylindrical perforate inner tube spaced therefrom and concentric therewith, a generally cylindrical membrane extending from said inner tube to said outer tube, the outer surface of said membrane being undulated in the axial direction to define axial passages with said outer tube forming a first compartment, the interior of said inner tube forming a hot second compartment separated from said first compartment by said membrane, a condenser havirciig inlet and outlet means, said first compartment, aspirating outlet means connected to sai means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and haVing an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane haVing osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment.

4. A refrigerating system including a receiver-vaporizer comprising a cool cylindrical imperforate outer tube and a cylindrical perforate inner tube spaced therefrom and concentric therewith, a generally cylindrical membrane extending from said inner tube toward said outer tube but stopping short thereof to form a space, sleeve means filling said space and including pores forming a first compartment, the interior of said inner tube forming a hot second compartment separated from said first compartment by said membrane, a condenser having inlet and outlet means, said outlet means connected to said first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a lowpressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane haVing osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment.

10107.5 (Hill 

1. A refrigerating system including a receiver-vaporizer-type compressor having an enclosure and a membrane dividing said enclosure into cooler first and warmer second compartments, a condenser having inlet and outlet means, said outlet means connected to said first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane having osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment.
 2. A refrigerating system including a receiver-vaporizer-type compressor having an enclosure and a membrane dividing said enclosure into cool first and hot second compartments, a condenser havIng inlet and outlet means, said outlet means connected to said first first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane having osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment, said, evaporate circuit including a heat exchanger having a first portion between the inlet of said evaporative circuit and said restrictor and having a second portion between said evaporator and the outlet of said evaporative circuit, said first and second portions being in heat exchange relation.
 3. A refrigerating system including a receiver-vaporizer comprising a cool cylindrical imperforate outer tube and a cylindrical perforate inner tube spaced therefrom and concentric therewith, a generally cylindrical membrane extending from said inner tube to said outer tube, the outer surface of said membrane being undulated in the axial direction to define axial passages with said outer tube forming a first compartment, the interior of said inner tube forming a hot second compartment separated from said first compartment by said membrane, a condenser haVing inlet and outlet means, said outlet means connected to said first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and haVing an outlet, said aspirating means having a low pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane haVing osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment.
 4. A refrigerating system including a receiver-vaporizer comprising a cool cylindrical imperforate outer tube and a cylindrical perforate inner tube spaced therefrom and concentric therewith, a generally cylindrical membrane extending from said inner tube toward said outer tube but stopping short thereof to form a space, sleeve means filling said space and including pores forming a first compartment, the interior of said inner tube forming a hot second compartment separated from said first compartment by said membrane, a condenser having inlet and outlet means, said outlet means connected to said first compartment, aspirating means having a primary inlet connected to said second compartment and having an outlet connected to said condenser inlet means, an evaporative circuit portion having an inlet connected to said condenser outlet means and having a restrictor and evaporator connected in series and having an outlet, said aspirating means having a low-pressure secondary inlet connected to the outlet of said evaporative circuit, said refrigerating system containing a refrigerant and means in said second compartment for vaporizing said refrigerant, said membrane haVing osmotic properties for passing the refrigerant through the membrane from the first compartment to the second compartment. 